How long can I use the myblu™ battery for before it needs to be recharged? February 03, 2020 08:51 Updated When fully charged, the myblu™ battery should last for roughly 8 hours, although individual use will vary. Related articles How do I know when the myblu™ battery needs to be recharged? Why is my battery not holding a charge? Can I use my existing blu® Wall Charger to charge the myblu™ ? Why is my battery flashing? Where can I purchase the myblu™ Kit?